1. Field of the Invention
The present invention generally relates to collection of cell colonies grown on culture media and, more particularly, is concerned with a cell scraper device having a blade on a pair of handles with pivotal joints connecting the blade to the handles.
2. Description of the Prior Art
Microorganisms are often grown by scientists and others on culture media in petri dishes, culture flasks or the like, for various reasons. Cell colonies grown on culture media are typically grown across a mono-layer of culture medium on a treated plastic surface. The surface is generally treated with a substrate which is usually a chemical coating attached to the plastic. The substrate allows for high densities of cells to grow over a given surface area.
After a predetermined period of time when maximum cell growth is achieved, the cells are ready to be harvested, which involves lifting and removing intact layers of cells from the culture medium. The cells are suspended in the culture medium when they are lifted from the surface of the dish or flask and are decanted into tubes or other containers for further use or analysis. Special care must be taken during this process so that the viability of the cells is maintained and a maximum level of cell recovery is achieved.
A variety of devices have been developed over the years for collecting cell colonies grown on culture media and/or for inoculating culture media with cell colonies. Representative examples of prior art cell colony collection and/or inoculation devices are disclosed in U.S. Pat. No. 4,010,077 to Pardos, U.S. Pat. No. 4,687,746 to Rosenberg et al., U.S. Pat. No. 4,892,831 to Wong, U.S. Pat. No. 5,462,063 to Kist et al. and U.S. Des. Pat. No. 350,603 to Firlik. The Pardos patent discloses a transfer device which includes a plurality of circumferentially spaced fingers extending generally in a common axial direction from a base and diverging from one another. The Rosenberg et al. patent discloses a transfer device which includes a tip at one end of a handle and a loop at the other end of the handle. The Wong patent discloses an inoculating device which includes a loop at one end of a handle and a picker with a pyramidal-shaped head at the other end of the handle. The Kist et al. patent discloses a cell collecting device which includes a handle and a brush head formed of flexible bristles. The bristles can be arranged such that central bristles are surrounded by outer bristles that are shorter and thinner than the central bristles. The bristles can also be arranged in a pattern of concentric circles. The Firlik patent discloses a cell culture scraper which includes a handle and a plate with serrations along an edge thereof at one end of the handle. The fingers of the Pardos device, the tip and loop of the Rosenberg et al. device, the loop and picker of the Wong device, the brush of the Kist et al. device and the plate with serrations of the Firlik device are all adapted to be used to collect a bacteriological specimen or to plate or streak cells on a growth medium. There are other prior art devices known as "cell lifters" or "cell scrapers" which are available to lift or scrape cells from surfaces and into culture media for decanting.
While these prior art cell colony collection and inoculation devices appear to be satisfactory in use for the specific purposes for which they were designed, none of them seem to provide an effective solution for collecting layers of cells which are grown on media inside culture flasks. The problem with these prior art devices is that they do not adequately or easily reach or access the entire interior surface of a tissue culture flask. In addition, their features can cause significant loss of viable cell populations due to damage to cell walls in the process of contacting and scraping the cells from wall surfaces.
Consequently, a need still exists for a device which provides a more effective solution to the aforementioned problems of the prior art devices without introducing any new problems in place thereof.